Service chaining is being widely adopted in a networking industry as a means of dynamically creating a sequence of virtual service functions (SFs) that can be applied to a traffic stream in a virtual network environment. In the virtual network environment, each virtual service function may be deployed on one of many physical nodes in a data center. A service chain may be created that specifies a sequence of port pairs, each having an ingress port and an egress port of a service function. Each node has a hypervisor that hosts virtual machines (VMs) on which the service functions are implemented, and also a virtual switch that steers traffic to each VM.
There may be cases where the service functions are deployed on different sub-networks. In the virtual network environment, these sub-networks are inter-connected using virtual routers.